Tooth and root conditions in the middle-aged and the elderly in Hong Kong.

In an oral health survey of Hong Kong Chinese conducted in 1991, a sample of 372 35-44-yr-olds and 537 noninstitutionalized 65-74-yr-olds were interviewed and clinically examined. The examination procedures, instruments, and diagnostic criteria used to detect coronal caries followed those recommended by the World Health Organization (1987). The diagnostic criteria used to assess root-surface caries were based on those used in a national oral health survey of US employed adults (National Institute of Dental Research, 1987). Calibration of examiners was conducted before the survey and the interexaminer reliability was found to be very high; the kappa statistics were 0.93 and 0.91 for the younger and older age groups, respectively. None of the 35-44-yr-olds were edentulous and 96% had 21 teeth or more. The prevalence of edentulousness among the elderly was 12%. The DMFT indices of the younger and older age groups were 8.7 and 18.9, respectively. In both age groups, MT was the major component of the DMFT index, and female subjects had a slightly higher score. The prevalences of decayed/filled roots were 7% and 26% for the 35-44- and 65-74-yr-olds, respectively. As compared with previous surveys conducted in Hong Kong, there has been a 40% reduction in the DMFT index of the 35-44-yr-olds since 1968, but little change in the tooth and root conditions was noted between 1984 and 1991.